Genetics/Evolution, Research Methods
An identical pair of genes on 2 chromosomes
Homozygous
The most important ions for nerve impulses
Sodium (NA+) and Potassium (K+)
a chemical, released at a synapse, that affects another neuron
neurotransmitter (EX: glutamate, GABA, acetylcholine)
How do we know about resting potentials?
Insert microelectrode into the cell, and one outside of the cell and read the difference in voltage
How does myelin increase conduction of action potentals?
saltatory conduction- the action potentials can jump over the Nodes of Ranvier and jump node to node.
The full hereditary information
Genotype
What are the major parts of the neuron and what do they do?
Axon: sends information
Dendrite: receives information
Cell body (soma): controls metabolic function
Ionotropic receptor
A method of studying for heritability
Adopted kids- do traits resemble biological parents or parents who raised them?
Twins- monozygotic vs dizygotic
Describe the concentration of sodium and potassium inside/outside the cell at rest
Na+ is more concentrated outside the cell
K+ is more concentrated inside the cell
Produces proteins that increase the probability that a behavior will develop under certain circumstances
Genes
What keeps out viruses/bacteria/chemicals from the blood vessels of the brain?
Blood-brain barrier
Describe the reflex arch
1. Sensory neuron senses touch
2. Excites intrinsic neuron
3. Intrinsic neuron excites motor neuron
4. motor neuron excites muscle
How can you get an Excitatory Post Synaptic Potential (EPSP)?
Stimulate the presynaptic neuron with an electrode. Stimulate enough to record a depolarization that doesn't reach threshold to create an action potential.
Describe the concentration of sodium and potassium inside/outside the cell when it depolarizes
Sodium rushes into the cell, the outside of the cell becomes more negative
Research method used by injecting radioactive chemicals that are used by the brain (typically glucose)
PET (Positron Emission Tomography)
How do you get an action potential?
stimulation beyond threshold
What are vesicles and what role do they play in neuronal communication?
Vesicles are tiny packets of neurotransmitters, allow them to be released at the synaptic cleft between the post and pre-synaptic terminals
What were Sherrington's 3 observations about reflexes
1. Reflexes are slower than conduction along an axon
2. Several weak stimuli at different times or locations produce a reflex together that they don't produce individually
3. When one set of muscles is excited, another set is relaxed
Describe what is happening to sodium and potassium during the "falling phase" of an actional potential
Potassium exits the cell once the inside becomes positive (from Na+ entering)
What does fMRI show and how?
Shows active parts of the brain by measuring changes in blood flow and oxygen present in the blood
What are the types of glial cells and what do they do?
Astrocytes: dilate blood vessels
Microglia: immune cells in brain/spinal cord
Oligodendrocytes/Schwann cells: brain/periphery, build/protect myelin
Radial glia: guide neurons and dendrites during development
What happens when the action potential reaches the presynaptic terminal?
Calcium enters the cell, neurotransmitters are released and bind to the receptors of the postsynaptic neuron
What was Lowei's experiment and what did he find?
Experiment:
- Stimulate the vagus nerve of Frog A to decrease heart rate
- Collect fluid from around Frog A's heart and transfer it to Frog B's heart.
- Frog B's heart rate decreases without ever stimulating its nerves
Results: nerves stimulate muscle by releasing chemicals
What forces are acting on sodium and potassium at rest?
Sodium: electrical gradient pulling in(sodium is +, inside of the cell is -), concentration gradient pulling in( more sodium outside the cell, less inside the cell, being pulled in)
Potassium: electrical gradient pulling in (potassium is +, inside cell is -), concentration gradient pushing out (more potassium inside the cell, less outside)